/Engine/Plugins/Experimental/Mutable/Source/CustomizableObjectEditor/Classes/MuCOE/Nodes/CustomizableObjectNodeMaterial.h
Returns the reference texture assigned to a Material Texture Parameter.
nullptr if it does not have one assigned.
[UTexture2D](API\Runtime\Engine\Engine\UTexture2D) * GetImageReferenceTexture ( int32 ImageIndex ) const